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import abc
import asyncio
import collections
import re
import string
import zlib
from contextlib import suppress
from enum import IntEnum
from typing import (
Any,
Generic,
List,
NamedTuple,
Optional,
Pattern,
Set,
Tuple,
Type,
TypeVar,
Union,
cast,
)
from multidict import CIMultiDict, CIMultiDictProxy, istr
from yarl import URL
from . import hdrs
from .base_protocol import BaseProtocol
from .helpers import NO_EXTENSIONS, BaseTimerContext
from .http_exceptions import (
BadHttpMessage,
BadStatusLine,
ContentEncodingError,
ContentLengthError,
InvalidHeader,
LineTooLong,
TransferEncodingError,
)
from .http_writer import HttpVersion, HttpVersion10
from .log import internal_logger
from .streams import EMPTY_PAYLOAD, StreamReader
from .typedefs import Final, RawHeaders
try:
import brotli
HAS_BROTLI = True
except ImportError: # pragma: no cover
HAS_BROTLI = False
__all__ = (
"HeadersParser",
"HttpParser",
"HttpRequestParser",
"HttpResponseParser",
"RawRequestMessage",
"RawResponseMessage",
)
ASCIISET: Final[Set[str]] = set(string.printable)
# See https://tools.ietf.org/html/rfc7230#section-3.1.1
# and https://tools.ietf.org/html/rfc7230#appendix-B
#
# method = token
# tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
# "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA
# token = 1*tchar
METHRE: Final[Pattern[str]] = re.compile(r"[!#$%&'*+\-.^_`|~0-9A-Za-z]+")
VERSRE: Final[Pattern[str]] = re.compile(r"HTTP/(\d+).(\d+)")
HDRRE: Final[Pattern[bytes]] = re.compile(rb"[\x00-\x1F\x7F()<>@,;:\[\]={} \t\\\\\"]")
class RawRequestMessage(NamedTuple):
method: str
path: str
version: HttpVersion
headers: "CIMultiDictProxy[str]"
raw_headers: RawHeaders
should_close: bool
compression: Optional[str]
upgrade: bool
chunked: bool
url: URL
RawResponseMessage = collections.namedtuple(
"RawResponseMessage",
[
"version",
"code",
"reason",
"headers",
"raw_headers",
"should_close",
"compression",
"upgrade",
"chunked",
],
)
_MsgT = TypeVar("_MsgT", RawRequestMessage, RawResponseMessage)
class ParseState(IntEnum):
PARSE_NONE = 0
PARSE_LENGTH = 1
PARSE_CHUNKED = 2
PARSE_UNTIL_EOF = 3
class ChunkState(IntEnum):
PARSE_CHUNKED_SIZE = 0
PARSE_CHUNKED_CHUNK = 1
PARSE_CHUNKED_CHUNK_EOF = 2
PARSE_MAYBE_TRAILERS = 3
PARSE_TRAILERS = 4
class HeadersParser:
def __init__(
self,
max_line_size: int = 8190,
max_headers: int = 32768,
max_field_size: int = 8190,
) -> None:
self.max_line_size = max_line_size
self.max_headers = max_headers
self.max_field_size = max_field_size
def parse_headers(
self, lines: List[bytes]
) -> Tuple["CIMultiDictProxy[str]", RawHeaders]:
headers = CIMultiDict() # type: CIMultiDict[str]
raw_headers = []
lines_idx = 1
line = lines[1]
line_count = len(lines)
while line:
# Parse initial header name : value pair.
try:
bname, bvalue = line.split(b":", 1)
except ValueError:
raise InvalidHeader(line) from None
bname = bname.strip(b" \t")
bvalue = bvalue.lstrip()
if HDRRE.search(bname):
raise InvalidHeader(bname)
if len(bname) > self.max_field_size:
raise LineTooLong(
"request header name {}".format(
bname.decode("utf8", "xmlcharrefreplace")
),
str(self.max_field_size),
str(len(bname)),
)
header_length = len(bvalue)
# next line
lines_idx += 1
line = lines[lines_idx]
# consume continuation lines
continuation = line and line[0] in (32, 9) # (' ', '\t')
if continuation:
bvalue_lst = [bvalue]
while continuation:
header_length += len(line)
if header_length > self.max_field_size:
raise LineTooLong(
"request header field {}".format(
bname.decode("utf8", "xmlcharrefreplace")
),
str(self.max_field_size),
str(header_length),
)
bvalue_lst.append(line)
# next line
lines_idx += 1
if lines_idx < line_count:
line = lines[lines_idx]
if line:
continuation = line[0] in (32, 9) # (' ', '\t')
else:
line = b""
break
bvalue = b"".join(bvalue_lst)
else:
if header_length > self.max_field_size:
raise LineTooLong(
"request header field {}".format(
bname.decode("utf8", "xmlcharrefreplace")
),
str(self.max_field_size),
str(header_length),
)
bvalue = bvalue.strip()
name = bname.decode("utf-8", "surrogateescape")
value = bvalue.decode("utf-8", "surrogateescape")
headers.add(name, value)
raw_headers.append((bname, bvalue))
return (CIMultiDictProxy(headers), tuple(raw_headers))
class HttpParser(abc.ABC, Generic[_MsgT]):
def __init__(
self,
protocol: Optional[BaseProtocol] = None,
loop: Optional[asyncio.AbstractEventLoop] = None,
limit: int = 2 ** 16,
max_line_size: int = 8190,
max_headers: int = 32768,
max_field_size: int = 8190,
timer: Optional[BaseTimerContext] = None,
code: Optional[int] = None,
method: Optional[str] = None,
readall: bool = False,
payload_exception: Optional[Type[BaseException]] = None,
response_with_body: bool = True,
read_until_eof: bool = False,
auto_decompress: bool = True,
) -> None:
self.protocol = protocol
self.loop = loop
self.max_line_size = max_line_size
self.max_headers = max_headers
self.max_field_size = max_field_size
self.timer = timer
self.code = code
self.method = method
self.readall = readall
self.payload_exception = payload_exception
self.response_with_body = response_with_body
self.read_until_eof = read_until_eof
self._lines = [] # type: List[bytes]
self._tail = b""
self._upgraded = False
self._payload = None
self._payload_parser = None # type: Optional[HttpPayloadParser]
self._auto_decompress = auto_decompress
self._limit = limit
self._headers_parser = HeadersParser(max_line_size, max_headers, max_field_size)
@abc.abstractmethod
def parse_message(self, lines: List[bytes]) -> _MsgT:
pass
def feed_eof(self) -> Optional[_MsgT]:
if self._payload_parser is not None:
self._payload_parser.feed_eof()
self._payload_parser = None
else:
# try to extract partial message
if self._tail:
self._lines.append(self._tail)
if self._lines:
if self._lines[-1] != "\r\n":
self._lines.append(b"")
with suppress(Exception):
return self.parse_message(self._lines)
return None
def feed_data(
self,
data: bytes,
SEP: bytes = b"\r\n",
EMPTY: bytes = b"",
CONTENT_LENGTH: istr = hdrs.CONTENT_LENGTH,
METH_CONNECT: str = hdrs.METH_CONNECT,
SEC_WEBSOCKET_KEY1: istr = hdrs.SEC_WEBSOCKET_KEY1,
) -> Tuple[List[Tuple[_MsgT, StreamReader]], bool, bytes]:
messages = []
if self._tail:
data, self._tail = self._tail + data, b""
data_len = len(data)
start_pos = 0
loop = self.loop
while start_pos < data_len:
# read HTTP message (request/response line + headers), \r\n\r\n
# and split by lines
if self._payload_parser is None and not self._upgraded:
pos = data.find(SEP, start_pos)
# consume \r\n
if pos == start_pos and not self._lines:
start_pos = pos + 2
continue
if pos >= start_pos:
# line found
self._lines.append(data[start_pos:pos])
start_pos = pos + 2
# \r\n\r\n found
if self._lines[-1] == EMPTY:
try:
msg: _MsgT = self.parse_message(self._lines)
finally:
self._lines.clear()
def get_content_length() -> Optional[int]:
# payload length
length_hdr = msg.headers.get(CONTENT_LENGTH)
if length_hdr is None:
return None
try:
length = int(length_hdr)
except ValueError:
raise InvalidHeader(CONTENT_LENGTH)
if length < 0:
raise InvalidHeader(CONTENT_LENGTH)
return length
length = get_content_length()
# do not support old websocket spec
if SEC_WEBSOCKET_KEY1 in msg.headers:
raise InvalidHeader(SEC_WEBSOCKET_KEY1)
self._upgraded = msg.upgrade
method = getattr(msg, "method", self.method)
assert self.protocol is not None
# calculate payload
if (
(length is not None and length > 0)
or msg.chunked
and not msg.upgrade
):
payload = StreamReader(
self.protocol,
timer=self.timer,
loop=loop,
limit=self._limit,
)
payload_parser = HttpPayloadParser(
payload,
length=length,
chunked=msg.chunked,
method=method,
compression=msg.compression,
code=self.code,
readall=self.readall,
response_with_body=self.response_with_body,
auto_decompress=self._auto_decompress,
)
if not payload_parser.done:
self._payload_parser = payload_parser
elif method == METH_CONNECT:
assert isinstance(msg, RawRequestMessage)
payload = StreamReader(
self.protocol,
timer=self.timer,
loop=loop,
limit=self._limit,
)
self._upgraded = True
self._payload_parser = HttpPayloadParser(
payload,
method=msg.method,
compression=msg.compression,
readall=True,
auto_decompress=self._auto_decompress,
)
else:
if (
getattr(msg, "code", 100) >= 199
and length is None
and self.read_until_eof
):
payload = StreamReader(
self.protocol,
timer=self.timer,
loop=loop,
limit=self._limit,
)
payload_parser = HttpPayloadParser(
payload,
length=length,
chunked=msg.chunked,
method=method,
compression=msg.compression,
code=self.code,
readall=True,
response_with_body=self.response_with_body,
auto_decompress=self._auto_decompress,
)
if not payload_parser.done:
self._payload_parser = payload_parser
else:
payload = EMPTY_PAYLOAD
messages.append((msg, payload))
else:
self._tail = data[start_pos:]
data = EMPTY
break
# no parser, just store
elif self._payload_parser is None and self._upgraded:
assert not self._lines
break
# feed payload
elif data and start_pos < data_len:
assert not self._lines
assert self._payload_parser is not None
try:
eof, data = self._payload_parser.feed_data(data[start_pos:])
except BaseException as exc:
if self.payload_exception is not None:
self._payload_parser.payload.set_exception(
self.payload_exception(str(exc))
)
else:
self._payload_parser.payload.set_exception(exc)
eof = True
data = b""
if eof:
start_pos = 0
data_len = len(data)
self._payload_parser = None
continue
else:
break
if data and start_pos < data_len:
data = data[start_pos:]
else:
data = EMPTY
return messages, self._upgraded, data
def parse_headers(
self, lines: List[bytes]
) -> Tuple[
"CIMultiDictProxy[str]", RawHeaders, Optional[bool], Optional[str], bool, bool
]:
"""Parses RFC 5322 headers from a stream.
Line continuations are supported. Returns list of header name
and value pairs. Header name is in upper case.
"""
headers, raw_headers = self._headers_parser.parse_headers(lines)
close_conn = None
encoding = None
upgrade = False
chunked = False
# keep-alive
conn = headers.get(hdrs.CONNECTION)
if conn:
v = conn.lower()
if v == "close":
close_conn = True
elif v == "keep-alive":
close_conn = False
elif v == "upgrade":
upgrade = True
# encoding
enc = headers.get(hdrs.CONTENT_ENCODING)
if enc:
enc = enc.lower()
if enc in ("gzip", "deflate", "br"):
encoding = enc
# chunking
te = headers.get(hdrs.TRANSFER_ENCODING)
if te is not None:
if "chunked" == te.lower():
chunked = True
else:
raise BadHttpMessage("Request has invalid `Transfer-Encoding`")
if hdrs.CONTENT_LENGTH in headers:
raise BadHttpMessage(
"Content-Length can't be present with Transfer-Encoding",
)
return (headers, raw_headers, close_conn, encoding, upgrade, chunked)
def set_upgraded(self, val: bool) -> None:
"""Set connection upgraded (to websocket) mode.
:param bool val: new state.
"""
self._upgraded = val
class HttpRequestParser(HttpParser[RawRequestMessage]):
"""Read request status line.
Exception .http_exceptions.BadStatusLine
could be raised in case of any errors in status line.
Returns RawRequestMessage.
"""
def parse_message(self, lines: List[bytes]) -> RawRequestMessage:
# request line
line = lines[0].decode("utf-8", "surrogateescape")
try:
method, path, version = line.split(None, 2)
except ValueError:
raise BadStatusLine(line) from None
if len(path) > self.max_line_size:
raise LineTooLong(
"Status line is too long", str(self.max_line_size), str(len(path))
)
path_part, _hash_separator, url_fragment = path.partition("#")
path_part, _question_mark_separator, qs_part = path_part.partition("?")
# method
if not METHRE.match(method):
raise BadStatusLine(method)
# version
try:
if version.startswith("HTTP/"):
n1, n2 = version[5:].split(".", 1)
version_o = HttpVersion(int(n1), int(n2))
else:
raise BadStatusLine(version)
except Exception:
raise BadStatusLine(version)
# read headers
(
headers,
raw_headers,
close,
compression,
upgrade,
chunked,
) = self.parse_headers(lines)
if close is None: # then the headers weren't set in the request
if version_o <= HttpVersion10: # HTTP 1.0 must asks to not close
close = True
else: # HTTP 1.1 must ask to close.
close = False
return RawRequestMessage(
method,
path,
version_o,
headers,
raw_headers,
close,
compression,
upgrade,
chunked,
# NOTE: `yarl.URL.build()` is used to mimic what the Cython-based
# NOTE: parser does, otherwise it results into the same
# NOTE: HTTP Request-Line input producing different
# NOTE: `yarl.URL()` objects
URL.build(
path=path_part,
query_string=qs_part,
fragment=url_fragment,
encoded=True,
),
)
class HttpResponseParser(HttpParser[RawResponseMessage]):
"""Read response status line and headers.
BadStatusLine could be raised in case of any errors in status line.
Returns RawResponseMessage.
"""
def parse_message(self, lines: List[bytes]) -> RawResponseMessage:
line = lines[0].decode("utf-8", "surrogateescape")
try:
version, status = line.split(None, 1)
except ValueError:
raise BadStatusLine(line) from None
try:
status, reason = status.split(None, 1)
except ValueError:
reason = ""
if len(reason) > self.max_line_size:
raise LineTooLong(
"Status line is too long", str(self.max_line_size), str(len(reason))
)
# version
match = VERSRE.match(version)
if match is None:
raise BadStatusLine(line)
version_o = HttpVersion(int(match.group(1)), int(match.group(2)))
# The status code is a three-digit number
try:
status_i = int(status)
except ValueError:
raise BadStatusLine(line) from None
if status_i > 999:
raise BadStatusLine(line)
# read headers
(
headers,
raw_headers,
close,
compression,
upgrade,
chunked,
) = self.parse_headers(lines)
if close is None:
close = version_o <= HttpVersion10
return RawResponseMessage(
version_o,
status_i,
reason.strip(),
headers,
raw_headers,
close,
compression,
upgrade,
chunked,
)
class HttpPayloadParser:
def __init__(
self,
payload: StreamReader,
length: Optional[int] = None,
chunked: bool = False,
compression: Optional[str] = None,
code: Optional[int] = None,
method: Optional[str] = None,
readall: bool = False,
response_with_body: bool = True,
auto_decompress: bool = True,
) -> None:
self._length = 0
self._type = ParseState.PARSE_NONE
self._chunk = ChunkState.PARSE_CHUNKED_SIZE
self._chunk_size = 0
self._chunk_tail = b""
self._auto_decompress = auto_decompress
self.done = False
# payload decompression wrapper
if response_with_body and compression and self._auto_decompress:
real_payload = DeflateBuffer(
payload, compression
) # type: Union[StreamReader, DeflateBuffer]
else:
real_payload = payload
# payload parser
if not response_with_body:
# don't parse payload if it's not expected to be received
self._type = ParseState.PARSE_NONE
real_payload.feed_eof()
self.done = True
elif chunked:
self._type = ParseState.PARSE_CHUNKED
elif length is not None:
self._type = ParseState.PARSE_LENGTH
self._length = length
if self._length == 0:
real_payload.feed_eof()
self.done = True
else:
if readall and code != 204:
self._type = ParseState.PARSE_UNTIL_EOF
elif method in ("PUT", "POST"):
internal_logger.warning( # pragma: no cover
"Content-Length or Transfer-Encoding header is required"
)
self._type = ParseState.PARSE_NONE
real_payload.feed_eof()
self.done = True
self.payload = real_payload
def feed_eof(self) -> None:
if self._type == ParseState.PARSE_UNTIL_EOF:
self.payload.feed_eof()
elif self._type == ParseState.PARSE_LENGTH:
raise ContentLengthError(
"Not enough data for satisfy content length header."
)
elif self._type == ParseState.PARSE_CHUNKED:
raise TransferEncodingError(
"Not enough data for satisfy transfer length header."
)
def feed_data(
self, chunk: bytes, SEP: bytes = b"\r\n", CHUNK_EXT: bytes = b";"
) -> Tuple[bool, bytes]:
# Read specified amount of bytes
if self._type == ParseState.PARSE_LENGTH:
required = self._length
chunk_len = len(chunk)
if required >= chunk_len:
self._length = required - chunk_len
self.payload.feed_data(chunk, chunk_len)
if self._length == 0:
self.payload.feed_eof()
return True, b""
else:
self._length = 0
self.payload.feed_data(chunk[:required], required)
self.payload.feed_eof()
return True, chunk[required:]
# Chunked transfer encoding parser
elif self._type == ParseState.PARSE_CHUNKED:
if self._chunk_tail:
chunk = self._chunk_tail + chunk
self._chunk_tail = b""
while chunk:
# read next chunk size
if self._chunk == ChunkState.PARSE_CHUNKED_SIZE:
pos = chunk.find(SEP)
if pos >= 0:
i = chunk.find(CHUNK_EXT, 0, pos)
if i >= 0:
size_b = chunk[:i] # strip chunk-extensions
else:
size_b = chunk[:pos]
try:
size = int(bytes(size_b), 16)
except ValueError:
exc = TransferEncodingError(
chunk[:pos].decode("ascii", "surrogateescape")
)
self.payload.set_exception(exc)
raise exc from None
chunk = chunk[pos + 2 :]
if size == 0: # eof marker
self._chunk = ChunkState.PARSE_MAYBE_TRAILERS
else:
self._chunk = ChunkState.PARSE_CHUNKED_CHUNK
self._chunk_size = size
self.payload.begin_http_chunk_receiving()
else:
self._chunk_tail = chunk
return False, b""
# read chunk and feed buffer
if self._chunk == ChunkState.PARSE_CHUNKED_CHUNK:
required = self._chunk_size
chunk_len = len(chunk)
if required > chunk_len:
self._chunk_size = required - chunk_len
self.payload.feed_data(chunk, chunk_len)
return False, b""
else:
self._chunk_size = 0
self.payload.feed_data(chunk[:required], required)
chunk = chunk[required:]
self._chunk = ChunkState.PARSE_CHUNKED_CHUNK_EOF
self.payload.end_http_chunk_receiving()
# toss the CRLF at the end of the chunk
if self._chunk == ChunkState.PARSE_CHUNKED_CHUNK_EOF:
if chunk[:2] == SEP:
chunk = chunk[2:]
self._chunk = ChunkState.PARSE_CHUNKED_SIZE
else:
self._chunk_tail = chunk
return False, b""
# if stream does not contain trailer, after 0\r\n
# we should get another \r\n otherwise
# trailers needs to be skiped until \r\n\r\n
if self._chunk == ChunkState.PARSE_MAYBE_TRAILERS:
head = chunk[:2]
if head == SEP:
# end of stream
self.payload.feed_eof()
return True, chunk[2:]
# Both CR and LF, or only LF may not be received yet. It is
# expected that CRLF or LF will be shown at the very first
# byte next time, otherwise trailers should come. The last
# CRLF which marks the end of response might not be
# contained in the same TCP segment which delivered the
# size indicator.
if not head:
return False, b""
if head == SEP[:1]:
self._chunk_tail = head
return False, b""
self._chunk = ChunkState.PARSE_TRAILERS
# read and discard trailer up to the CRLF terminator
if self._chunk == ChunkState.PARSE_TRAILERS:
pos = chunk.find(SEP)
if pos >= 0:
chunk = chunk[pos + 2 :]
self._chunk = ChunkState.PARSE_MAYBE_TRAILERS
else:
self._chunk_tail = chunk
return False, b""
# Read all bytes until eof
elif self._type == ParseState.PARSE_UNTIL_EOF:
self.payload.feed_data(chunk, len(chunk))
return False, b""
class DeflateBuffer:
"""DeflateStream decompress stream and feed data into specified stream."""
decompressor: Any
def __init__(self, out: StreamReader, encoding: Optional[str]) -> None:
self.out = out
self.size = 0
self.encoding = encoding
self._started_decoding = False
if encoding == "br":
if not HAS_BROTLI: # pragma: no cover
raise ContentEncodingError(
"Can not decode content-encoding: brotli (br). "
"Please install `Brotli`"
)
class BrotliDecoder:
# Supports both 'brotlipy' and 'Brotli' packages
# since they share an import name. The top branches
# are for 'brotlipy' and bottom branches for 'Brotli'
def __init__(self) -> None:
self._obj = brotli.Decompressor()
def decompress(self, data: bytes) -> bytes:
if hasattr(self._obj, "decompress"):
return cast(bytes, self._obj.decompress(data))
return cast(bytes, self._obj.process(data))
def flush(self) -> bytes:
if hasattr(self._obj, "flush"):
return cast(bytes, self._obj.flush())
return b""
self.decompressor = BrotliDecoder()
else:
zlib_mode = 16 + zlib.MAX_WBITS if encoding == "gzip" else zlib.MAX_WBITS
self.decompressor = zlib.decompressobj(wbits=zlib_mode)
def set_exception(self, exc: BaseException) -> None:
self.out.set_exception(exc)
def feed_data(self, chunk: bytes, size: int) -> None:
if not size:
return
self.size += size
# RFC1950
# bits 0..3 = CM = 0b1000 = 8 = "deflate"
# bits 4..7 = CINFO = 1..7 = windows size.
if (
not self._started_decoding
and self.encoding == "deflate"
and chunk[0] & 0xF != 8
):
# Change the decoder to decompress incorrectly compressed data
# Actually we should issue a warning about non-RFC-compliant data.
self.decompressor = zlib.decompressobj(wbits=-zlib.MAX_WBITS)
try:
chunk = self.decompressor.decompress(chunk)
except Exception:
raise ContentEncodingError(
"Can not decode content-encoding: %s" % self.encoding
)
self._started_decoding = True
if chunk:
self.out.feed_data(chunk, len(chunk))
def feed_eof(self) -> None:
chunk = self.decompressor.flush()
if chunk or self.size > 0:
self.out.feed_data(chunk, len(chunk))
if self.encoding == "deflate" and not self.decompressor.eof:
raise ContentEncodingError("deflate")
self.out.feed_eof()
def begin_http_chunk_receiving(self) -> None:
self.out.begin_http_chunk_receiving()
def end_http_chunk_receiving(self) -> None:
self.out.end_http_chunk_receiving()
HttpRequestParserPy = HttpRequestParser
HttpResponseParserPy = HttpResponseParser
RawRequestMessagePy = RawRequestMessage
RawResponseMessagePy = RawResponseMessage
try:
if not NO_EXTENSIONS:
from ._http_parser import ( # type: ignore[import,no-redef]
HttpRequestParser,
HttpResponseParser,
RawRequestMessage,
RawResponseMessage,
)
HttpRequestParserC = HttpRequestParser
HttpResponseParserC = HttpResponseParser
RawRequestMessageC = RawRequestMessage
RawResponseMessageC = RawResponseMessage
except ImportError: # pragma: no cover
pass
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